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Gartner identifies the top 10 strategic technology trends for 2018

October 6, 2017

Gartner, Inc. this week highlighted the top strategic technology trends that will impact most organizations in 2018. Analysts presented their findings during Gartner Symposium/ITxpo, which took place through Thursday.

Gartner defines a strategic technology trend as one with substantial disruptive potential that is beginning to break out of an emerging state into broader impact and use, or which are rapidly growing trends with a high degree of volatility reaching tipping points over the next five years.

“Gartner’s top 10 strategic technology trends for 2018 tie into the Intelligent Digital Mesh. The intelligent digital mesh is a foundation for future digital business and ecosystems,” said David Cearley, vice president and Gartner Fellow. “IT leaders must factor these technology trends into their innovation strategies or risk losing ground to those that do.”

The first three strategic technology trends explore how artificial intelligence (AI) and machine learning are seeping into virtually everything and represent a major battleground for technology providers over the next five years. The next four trends focus on blending the digital and physical worlds to create an immersive, digitally enhanced environment. The last three refer to exploiting connections between an expanding set of people and businesses, as well as devices, content and services to deliver digital business outcomes.

The top 10 strategic technology trends for 2018 are:

AI Foundation
Creating systems that learn, adapt and potentially act autonomously will be a major battleground for technology vendors through at least 2020. The ability to use AI to enhance decision making, reinvent business models and ecosystems, and remake the customer experience will drive the payoff for digital initiatives through 2025.

“AI techniques are evolving rapidly and organizations will need to invest significantly in skills, processes and tools to successfully exploit these techniques and build AI-enhanced systems,” said Mr. Cearley. “Investment areas can include data preparation, integration, algorithm and training methodology selection, and model creation. Multiple constituencies including data scientists, developers and business process owners will need to work together.”

Intelligent Apps and Analytics
Over the next few years, virtually every app, application and service will incorporate some level of AI. Some of these apps will be obvious intelligent apps that could not exist without AI and machine learning. Others will be unobtrusive users of AI that provide intelligence behind the scenes. Intelligent apps create a new intelligent intermediary layer between people and systems and have the potential to transform the nature of work and the structure of the workplace.

“Explore intelligent apps as a way of augmenting human activity and not simply as a way of replacing people,” said Mr. Cearley. “Augmented analytics is a particularly strategic growing area which uses machine learning to automate data preparation, insight discovery and insight sharing for a broad range of business users, operational workers and citizen data scientists.”

AI has become the next major battleground in a wide range of software and service markets, including aspects of enterprise resource planning (ERP). Packaged software and service providers should outline how they’ll be using AI to add business value in new versions in the form of advanced analytics, intelligent processes and advanced user experiences.

Intelligent Things
Intelligent things are physical things that go beyond the execution of rigid programming models to exploit AI to deliver advanced behaviors and interact more naturally with their surroundings and with people. AI is driving advances for new intelligent things (such as autonomous vehicles, robots and drones) and delivering enhanced capability to many existing things (such as Internet of Things [IoT] connected consumer and industrial systems).

“Currently, the use of autonomous vehicles in controlled settings (for example, in farming and mining) is a rapidly growing area of intelligent things. We are likely to see examples of autonomous vehicles on limited, well-defined and controlled roadways by 2022, but general use of autonomous cars will likely require a person in the driver’s seat in case the technology should unexpectedly fail,” said Mr. Cearley. “For at least the next five years, we expect that semiautonomous scenarios requiring a driver will dominate. During this time, manufacturers will test the technology more rigorously, and the nontechnology issues such as regulations, legal issues and cultural acceptance will be addressed.”

Digital Twin
A digital twin refers to the digital representation of a real-world entity or system. Digital twins in the context of IoT projects is particularly promising over the next three to five years and is leading the interest in digital twins today. Well-designed digital twins of assets have the potential to significantly improve enterprise decision making. These digital twins are linked to their real-world counterparts and are used to understand the state of the thing or system, respond to changes, improve operations and add value. Organizations will implement digital twins simply at first, then evolve them over time, improving their ability to collect and visualize the right data, apply the right analytics and rules, and respond effectively to business objectives.

“Over time, digital representations of virtually every aspect of our world will be connected dynamically with their real-world counterpart and with one another and infused with AI-based capabilities to enable advanced simulation, operation and analysis,” said Mr. Cearley. “City planners, digital marketers, healthcare professionals and industrial planners will all benefit from this long-term shift to the integrated digital twin world.”

Cloud to the Edge
Edge computing describes a computing topology in which information processing, and content collection and delivery, are placed closer to the sources of this information. Connectivity and latency challenges, bandwidth constraints and greater functionality embedded at the edge favors distributed models. Enterprises should begin using edge design patterns in their infrastructure architectures — particularly for those with significant IoT elements.

While many view cloud and edge as competing approaches, cloud is a style of computing where elastically scalable technology capabilities are delivered as a service and does not inherently mandate a centralized model.

“When used as complementary concepts, cloud can be the style of computing used to create a service-oriented model and a centralized control and coordination structure with edge being used as a delivery style allowing for disconnected or distributed process execution of aspects of the cloud service,” said Mr. Cearley.

Conversational Platforms
Conversational platforms will drive the next big paradigm shift in how humans interact with the digital world. The burden of translating intent shifts from user to computer. The platform takes a question or command from the user and then responds by executing some function, presenting some content or asking for additional input. Over the next few years, conversational interfaces will become a primary design goal for user interaction and be delivered in dedicated hardware, core OS features, platforms and applications.

“Conversational platforms have reached a tipping point in terms of understanding language and basic user intent, but they still fall short,” said Mr. Cearley. “The challenge that conversational platforms face is that users must communicate in a very structured way, and this is often a frustrating experience. A primary differentiator among conversational platforms will be the robustness of their conversational models and the application programming interface (API) and event models used to access, invoke and orchestrate third-party services to deliver complex outcomes.”

Immersive Experience
While conversational interfaces are changing how people control the digital world, virtual, augmented and mixed reality are changing the way that people perceive and interact with the digital world. The virtual reality (VR) and augmented reality (AR) market is currently adolescent and fragmented. Interest is high, resulting in many novelty VR applications that deliver little real business value outside of advanced entertainment, such as video games and 360-degree spherical videos. To drive real tangible business benefit, enterprises must examine specific real-life scenarios where VR and AR can be applied to make employees more productive and enhance the design, training and visualization processes.

Mixed reality, a type of immersion that merges and extends the technical functionality of both AR and VR, is emerging as the immersive experience of choice providing a compelling technology that optimizes its interface to better match how people view and interact with their world. Mixed reality exists along a spectrum and includes head-mounted displays (HMDs) for augmented or virtual reality as well as smartphone and tablet-based AR and use of environmental sensors. Mixed reality represents the span of how people perceive and interact with the digital world.

Blockchain
Blockchain is evolving from a digital currency infrastructure into a platform for digital transformation. Blockchain technologies offer a radical departure from the current centralized transaction and record-keeping mechanisms and can serve as a foundation of disruptive digital business for both established enterprises and startups. Although the hype surrounding blockchains originally focused on the financial services industry, blockchains have many potential applications, including government, healthcare, manufacturing, media distribution, identity verification, title registry and supply chain. Although it holds long-term promise and will undoubtedly create disruption, blockchain promise outstrips blockchain reality, and many of the associated technologies are immature for the next two to three years.

Event Driven
Central to digital business is the idea that the business is always sensing and ready to exploit new digital business moments. Business events could be anything that is noted digitally, reflecting the discovery of notable states or state changes, for example, completion of a purchase order, or an aircraft landing. With the use of event brokers, IoT, cloud computing, blockchain, in-memory data management and AI, business events can be detected faster and analyzed in greater detail. But technology alone without cultural and leadership change does not deliver the full value of the event-driven model. Digital business drives the need for IT leaders, planners and architects to embrace event thinking.

Continuous Adaptive Risk and Trust
To securely enable digital business initiatives in a world of advanced, targeted attacks, security and risk management leaders must adopt a continuous adaptive risk and trust assessment (CARTA) approach to allow real-time, risk and trust-based decision making with adaptive responses. Security infrastructure must be adaptive everywhere, to embrace the opportunity — and manage the risks — that comes delivering security that moves at the speed of digital business.

As part of a CARTA approach, organizations must overcome the barriers between security teams and application teams, much as DevOps tools and processes overcome the divide between development and operations. Information security architects must integrate security testing at multiple points into DevOps workflows in a collaborative way that is largely transparent to developers, and preserves the teamwork, agility and speed of DevOps and agile development environments, delivering “DevSecOps.” CARTA can also be applied at runtime with approaches such as deception technologies. Advances in technologies such as virtualization and software-defined networking has made it easier to deploy, manage and monitor “adaptive honeypots” — the basic component of network-based deception.

Gartner clients can learn more in the Gartner Special Report “Top Strategic Technology Trends for 2018.” Additional detailed analysis on each tech trend can be found in the Smarter With Gartner article “Gartner Top 10 Strategic Technology Trends for 2018.”

Power semiconductor sales rebounded in 2016 and will continue to grow through 2021

October 5, 2017

Global power semiconductor revenues grew year-over-year by 3.9 percent in 2016, reversing a 4.8 percent decline in 2015, according to a recent report from business information provider IHS Markit (Nasdaq: INFO).

All categories of power semiconductors (power discretes, power modules, and power integrated circuits) were up for the year, with the discretes market seeing the biggest jump. Sales in all regions increased, with China revenues topping the list. IHS Markit expects the market to grow by 7.5 percent in 2017, to $38.3 bill and achieve yearly increases through 2021.

Automotive and industrial lead the way

The automotive and industrial segments were particularly strong in 2016, with power semis in automotive growing by 7.0 percent and industrial by 5.0 percent. Advanced driver assistance systems (ADAS) – such as blind-spot detection, collision avoidance, and adaptive cruise control – are moving from luxury to mid-level vehicles, driving double digit increases for power semiconductors in that category.

Power semiconductors, especially power modules and discretes also saw sharp gains as the number of cars equipped with inverter systems for advanced start/stop and hybrid powertrains increased. In particular, power modules for cars and light trucks jumped 29.3 percent in 2016.

In the broad industrial sector the drive for energy efficiency improvement led to growth in renewable energy (solar and wind inverters), building and home control, and factory automation applications. Revenues from home appliances in the consumer segment also grew nicely as advanced motor control systems found their way into white goods, fans, kitchen, and cleaning products.

Despite good gains, other categories were flat to down. Power module sales for industrial motor drives, a large sub-segment, slid 1.1 percent and modules for traction applications were down 17.5 percent for the year. Power ICs for consumer application declined 4.9 percent while power discretes for lighting applications were off 2.7 percent.

Growth to continue

“The industry megatrends of vehicle electrification, advanced vehicle safety, energy efficiency and connected everything will continue to drive growth over the next five years,” said Kevin Anderson, senior analyst, power management for IHS Markit. “IHS Markit predicts that the compound-average annual growth rate (CAGR) from 2016 – 2021 will be 4.8 percent. Regionally, the highest growth is projected in China, at 6.0 percent CAGR, followed closely by the rest of Asia including Taiwan, Europe, Middle East and Africa, and the Americas – all with projected growth over 5 percent.”

Comparing XPoint memory architecture with NAND and DRAM products

October 3, 2017

By Dr. Jeongdong Choe, Senior Technical Fellow, TechInsights

There has been a great deal of speculation around the composition of Intel’s Optane™ XPoint memory technology: PCM or ReRAM, selector, layouts, patterning technology, technology node, multi-stacked cell structure, die floor plan, interconnection to each electrode (wordlines and bitlines), functional blocks, scalability and process integration.

TechInsights set about to find answers. We have analyzed Optane’s memory cell structure, materials, cell array and memory peripheral array design, layouts, process flow and circuitry. Our Advanced CMOS Essential (ACE) analyses on Intel’s XPoint memory presents our complete findings and market trend predictions. The following paragraphs present some of the highlights.

Intel XPoint memory is based on PCM and selector memory (storage) cell elements. GST-based PCM, Ge-Se-As-Si based Ovonic Threshold Switch (OTS) and two memory cell stacked array architecture are common across Intel’s and Micron’s XPoint technologies.

We examined effective memory cell area efficiency vs. memory array efficiency, and compared it to current DRAM and NAND products. In our previous analysis on XPoint memory die, we found that memory density per die is 0.62 Gb/mm² and memory efficiency is over 91%. The memory array efficiency, however, may not represent the reality because the memory peripheral and CMOS circuitry cover most of the die area.

We can define the effective cell area efficiency as a ratio of the real area of the cell memory elements (storage) to the total die area. For example, the effective memory cell area efficiency on Toshiba 15 nm 2D planar NAND is 43.9% due to excluding BC, CSL, SSL, GSL dummy wordlines and peripheral area on a die, while memory array efficiency is 72%. Figure 1 shows comparison of the effective memory cell area efficiency for 2D/3D NAND products from Toshiba/SanDisk (Western Digital), Micron/Intel, SK Hynix and Samsung, and 3D XPoint (Optane^TM from Intel).

Figure 1. A comparison of effective memory cell area efficiency on 2D/3D NAND and XPoint memory

When it comes to the effective unit cell size per 1 bit, NAND flash devices have been scaled down from 2D NAND (320 nm²) to 48L 3D NAND (145.8 nm²) or even to 64L 3D NAND (88.5 nm²) for Toshiba NAND products, while Intel Optane^TM two cell stacked XPoint memory has 800 nm² (effectively 2F²) (Figure 2).

Figure 2. A comparison of effective unit cell area per bit on 2D/3D NAND and XPoint memory

A comparison of memory density with DRAM products shown in Figure 3 illustrates that XPoint has higher memory density (0.62 Gb/mm²) than Samsung 1x nm (0.19 Gb/mm²), SK Hynix 2y nm (0.15 Gb/mm²) and Micron 20 nm (0.094 Gb/mm²) DRAM dice. Micron announced that the memory density of XPoint would be ten times higher than commercial DRAM products. This is true if we compare it with 30 nm class DRAM products, because most of the 30 nm class DRAM products from major DRAM manufacturers have 0.06 Gb/mm² memory density. The first commercial XPoint memory die has three times (vs. Samsung 1x DRAM) or six times (vs. Micron 20 nm DRAM) higher memory density than those of current DRAM products.

Figure 3. A comparison of die size and memory density on DRAM (25nm/20nm/18nm) and XPoint memory

We found that Intel introduced some innovative and compelling technologies on their first XPoint products such as PCM/OTS stack used for memory elements, GST based PCM, Ge-Se-As-Si based OTS and carbon based conductor and 2-bit cell stacked memory array with three electrodes. Intel successfully used a 20nm SADP double patterning technology to build a very uniform GST-based PCM/OTS memory square/island. Complete details on the of TechInsights’ XPoint memory analysis can be found here.

Click here to hear more from Dr. Choe and his TechInsights colleagues on 3D NAND.

Power transistor growth returns after volatile period

September 27, 2017

Since the 2009 semiconductor downturn and strong 2010 recovery year, power transistor sales have been rocked by market volatility, falling in three of the last five years because of inventory corrections and drawdowns by systems makers worried about ongoing economic weakness and price erosion in some product categories. After recovering from a 7% drop in 2015, power transistor sales grew 5% in 2016 to $12.9 billion and are forecast to set a new record high this year with worldwide revenues rising 6% to $13.6 billion, according to IC Insights’ 2017 O-S-D Report—A Market Analysis and Forecast for Optoelectronics, Sensors/Actuators, and Discrete Semiconductors.

The expected 2017 growth in power transistor sales will be the first back-to-back annual increase in this semiconductor market segment in six years, and that will push dollar volumes past the current record high of $13.5 billion set in 2011. In 2012 and 2013, power transistors suffered their first back-to-back annual sales decline in more than three decades—dropping 8% and 6%, respectively—after rising 12% in 2011 and surging 44% in the 2010 recovery from the 2009 downturn year. The power transistor market then rebounded in 2014 with a strong 14% increase, only to drop 7% in 2015. In 2016, this semiconductor discretes market category began to stabilize and is expected to continue expanding at a modest rate in the next several years, based on IC Insights’ O-S-D Report forecast (Figure 1).

Power transistors are the primary growth engine in the $23 billion discrete semiconductor market because they play a vital role in controlling and conditioning electricity for all types of electronics—including a growing number of battery-operated systems. Worldwide efforts to reduce the waste of power in electric utility grids have significantly increased the importance of power transistors in consumer, commercial, and industrial systems. Renewable-energy applications (e.g., wind and solar systems) as well as electric and hybrid vehicles have also become important applications for power transistors in the last 15 years.

Figure 1

However, volatility in the first half of this decade resulted in an uncharacteristic drop in market size for power transistors during the last five years. Between 2011 and 2016, power transistor sales fell by a compound annual growth rate of -0.9% compared to a 25-year historical annual average increase of 6.4% (between 1991 and 2016). The 2017 O-S-D Report is projecting that worldwide power transistor sales will grow by a CAGR of 4.2% between 2016 and 2021, reaching $15.8 billion in the final year of the forecast.

All power transistor technology categories are expected to register sales growth in 2017 with MOS field effect transistor (FET) products increasing 6% to nearly $7.7 billion, insulated-gate bipolar transistor (IGBT) products also rising 6% to $4.1 billion, and bipolar junction transistor products growing 4% to about $875 million. RF/microwave power transistors and module sales are forecast to rise 3% in 2017 to $960 million, according to the O-S-D Report.

Itâs gonna be a bright, bright sun-shiny day

September 26, 2017

BY ARABINDA DAS and JUN LU, TechInsights, Ottawa, ON

Last year was a great year for photovoltaic (PV) technology. According to Renewable Energy World magazine, since April 2016, 21 MW of solar PV mini-grids were announced in emerging markets [1]. The exact numbers of installed solar grids for 2016 has not been published yet but looking at the data for 2015, the PV industry is growing, helped by the $/watt for solar panels continuing to drop. The $/watt is obtained by taking the ratio of total cost of manufacturing and the number of watts generated. According to the Photovoltaic Magazine, the PV market continued to grow worldwide in 2015. The magazine also makes reference to the newly published report by the International Energy Agency Photovoltaic Power System (IEA PVPS) programme’s “Snapshot of Global Photovoltaic Markets 2015,” which also states that the total capacity around the globe has crossed the 200 GW benchmark and is continuing to grow [2]. This milestone of 200 GW in installed systems is a remarkable achievement and makes us think of the amazing journey of PV technology. The technology was born in Bell Labs, around 1954, with a solar cell efficiency of just 4% [3]. By the end of the 20th century, the overall solar cell efficiency was close to 11% and the worldwide installed capacity of PV was only 1 GW [3]. Today, seventeen years later, it has soared to 200 GW, with single junction cells having efficiencies around 20% [2].

Si-based solar cells

To celebrate this important milestone, we put TechInsights’ analysis and technical databases to work to investigate the structure of solar cells of two leading manufacturers and compare them to earlier technologies. We chose to analyze Si-based solar cells only, as they represent over 85% of the global market. According to the 2016 IHS Markit report, the top three PV module suppliers in the world are Trina Solar, SunPower, and First Solar [4]. We procured panels from Trina Solar, a Chinese based company, and SunPower, an American company, and carried out a structural analysis of these panels. These analyses helped us take a snapshot of current PV technology. We compared these two types of panels with an older panel from our database. This panel is about eight years old and was made by Kaneka (Japan). We will provide an overview of each panel and their underlying structure.

Table 1 consolidates some of the important param- eters of the three panels. The SunPower panel is based on monocrystalline silicon and the Trina solar panels are based on polycrystalline silicon. The older Kaneka panel is based on amorphous Si thin film technology. The panel from Kaneka is an earlier product; their recent products are made using hybrid technology, a combination of amorphous films and polycrystalline substrates, The Kaneka panel complements very well the other two products which are based on Si crystalline wafers. The technology to fabricate the solar cells (thin film, multi-crystalline or mono-crystalline) has a direct impact on the efficiency of the cells and on their electrical parameters like the open circuit voltage (Voc) and the short circuit current (Isc), as can be seen in Table 1. This table also shows that the Kaneka thin-film based panel has the lowest nominal power among the three. The ratio of nominal power to the light power that is received by the PV panel is indicative of its efficiency. It can be seen also that Kaneka’s thin film panel has the highest open circuit voltage which is the maximum voltage available from the solar cell without any load connected to it.

Table 1 indicates that SunPower is the only one among the three that uses an n-type substrate and has the highest solar efficiency. SunPower has the lowest weight per meter-square of all the panels assessed (9.3kg).

Unlike SunPower panels, most installed Si solar panels employ a p-type substrate, even though the first silicon-based solar cells developed at Bell Labs were based on n-type Si substrates [3]. Researchers J. Libal and R. Kopecek posit that the industry transitioned to p-type substrates because the initial usage of solar cells was in space applications and p-type wafers demonstrated less degradation in the presence of cosmic rays. They suggest that for terrestrial applications there is growing evidence that n-type based solar panels are preferred over p-type based panels [5]. The reasons for choosing n-type Si substrates rather than p-type substrates are because the former are less sensitive to metallic impurities and thus are less expensive to fabricate. In general, the minority carrier diffusion lengths in n-type substrates are higher than p-type Si substrates. Also, n-type Si substrates can withstand higher processing temperatures than p-type substrates, which are prone to boron diffusion. According to the International Technology Roadmap for Photovoltaic (ITRPV), n-type based substrates will increase in prevalence and may eventually replace the p-type monocrystalline Si cells [6].

Thin film based solar panels are very different from monocrystalline Si cells. Thin film cells have the lowest efficiency and yet they too have a role to play in the PV industry. They are the most versatile; they can be coated on different substrates such as glass, plastic or even flexible substrates. The other big advantage of amorphous solar films is that they can be manufac- tured in a range of shapes, even non-polygonal shapes, thus they can be used in various applications. Also, thin film solar panels are not affected by high temper- atures, unlike crystalline solar panels. Thin film based panels made from amorphous Si are more effective for wavelengths between 400 nm to 700 nm, which is also the sensitive spectrum of the human eye; thus they can be used as light sensors [7]. Usually, thin film panels are almost half the price of monocrystalline panels. Amorphous silicon solar cells only require 1% of the silicon used in crystalline silicon solar cells [7].

Multi-crystalline (MC) solar panels are also cheaper than monocrystalline solar panels. MC panels are made by melting raw silicon and confining them into square molds, where they are cooled. This MC-Si process does not require the expensive Czochralski process. In the early days, the cost of fabrication of MC-Si panels was higher than thin film based panels. Now, due to the major advances in fabrication technologies, these panels often have the best $/ watt, which represent the ratio of cost to manufacture to energy output [8]. It is difficult to compare $/watt directly from different manufacturers and different types of solar panels as the technology is manufacturing is changing rapidly and often the most recent products of a manufacturer are not compared. A more sensible factor of comparison would be the ratio of total kilowatt-hours the system generates in its lifetime divided by the cost per square unit of the panel. To make a detailed estimation even the installation cost and tolerance to shade, overall reliability must be included in the calculations, which is beyond the scope of this article.

Solar panel overview

FIGURE 1 shows the panel from Kaneka. It indicates that the Kaneka solar panel cells are long strips that run across the whole length of the panel. The color of the panels is a shade of purple. The Kaneka Solar which is amorphous Si-based, has a very uniform color. The inherent structure of amorphous Si-films has many structural defects because they are not crystalline and thus are tolerant to other defects like impurities during manufacturing, unlike crystalline based panels [7]. The color of the thin film panels is strongly thickness dependent because thickness affects the light absorption. A solar cell’s outward appearance can range from blue to black and is dependent on the absorption and reflectivity of their surface. Ideally, if the cell absorbs all the light impinging on the surface it should be black. FIGURE 2 shows the panels from Trina solar and Sunpower. The Trina Solar panel has a blueish color and each cell is perfectly square. The SunPower SPR-X20- 250-BLK solar cell has a uniform blackish color. The spacing between the cells, the interconnect resis- tance, the top contacts and the materials used for the connections affect the overall performance of the panel. All three manufacturers connect their cells within a PV module and PV modules within an array in a series configuration.

Table 2 summarizes the cell dimensions for the three manufacturers. Kaneka panels have the narrowest space (0.55mm) between the cells. The Trina solar panel has a 3 mm wide gap and a 5 mm gap, between two adjacent solar cells, in the horizontal and vertical direction respectively. These gaps are used for bus electrodes. In the SunPower solar panel, the metal grid is placed on the back surface eliminating metal finger width as a layout constraint. This design significantly reduces the finger resistance and improves the series resistance.

For all panels, interconnects are made between the cells. The metallization and interconnects between the cells is a field of technology on its own. There are various techniques like lithography, laser grooving and printed contacts and these details are discussed more in detail elsewhere [9, 10, 11].

Solar panel cross-sections

In this section, we look into the layers deposited on the substrates. Cross-sectioning these big panels is not a trivial feat. These panels are covered with tempered glass and shatter during sawing and cross-sectioning. To extract a small rectangular piece requires patience and involves sawing and grinding processes. In most cases, the glass was removed before doing the cross-section. FIGURE 3 illustrates two SEM cross-sectional images and one schematic drawing. The SEM cross-sectional images show the top and bottom part of the Kaneka solar cell. In figure 3(a), the active layers comprise indium- tin- oxide, an amorphous silicon layer capped with zinc oxide, silver and a very thin layer of Ni-Al. On top of the Ni-Al film, solder is deposited. Ni-Al provides better adhesion to solder. Two electrical contacts are made between the cells, one to the indium-tin-oxide for the back contact and the other to the Ni-Al layer. Figure 3(b) exposes the layers under the glass substrate. The rear surface of the glass substrate is covered by a soft material such as EVA (ethyl-vinyl-acetate), which in turn is covered by a rear Polyvinyl Fluoride (PVF) layer called the backsheet (Tedlar or similar). EVA is also used on the top surface (figure 3(a)). The usage of these layers is standard practice in the PV industry. The main function of these layers is that they are impervious to moisture and are stable under prolonged exposure to sunlight. On the front side, EVA also helps to reduce reflection and provides good adhesion between the top glass and the solar panels. Figure 3(c) shows the complete stack in the Kaneka solar cell.

FIGURE 4 presents the stack of materials on the multi- crystalline substrate of the Trina Solar panel. The substrate is p-type and has a very thin phosphorous doped region near the top surface. This n-doped region forms the PN junction. A silicon nitride anti-reflective coating layer is deposited on top of the substrate and in designated areas the passivation is opened and silver is deposited to make electrical contact to the n-doped regions. At the bottom of the multi-crystalline substrate, there is also a thin region of high p-doping concentration and this forms the back surface field layer. This solar cell module is fabricated using passivated emitter and full metal back-surface-field (BSF) technology. BSF technology is implemented to mitigate rear surface recombination and this is done by doping heavily at the rear surface of the substrate. This high doping concentration keeps minority carriers (electrons) away from the rear contact because the interface between the high and low doped areas of same conductivity acts like a diode and restricts the flow of the minority carriers to the rear surface. Passivated emitters in the front side and BSF layer on the rear side improve the efficiency of the cells. Figure 3(b) is the schematic repre- sentation of the cell without the EVA and PVF layers.

FIGURE 5 shows an optical cross-section of the SunPower cell. Figure 5(a) shows that SunPower employs a backside junction technology with interdigitated backside p-emitter and n-base metal. This means that both the contact’s n and p-electrodes are at the bottom of the substrate and are placed in in an alternating manner. Having all the metal contacts on the rear side has two big advantages:

1. Metallic contacts are reflective and occupy space that can be used to collect more sunlight; transferring these contacts to the rear side improves the cell efficiency and also leaves the front surface with a uniformly black color, which is more aesthetic for the home users.

2. It reduces bulk recombination. The mono-crystalline substrate is only 120 μm thick. It is designed so that the carrier is generated close to the junction. The substrate is n-type and p-electrodes are formed by localized doping on the bottom part of the substrate.

Figure 5(b) illustrates the general structure of the cell.

FIGURE 6 depicts a SEM cross-section of the metal fingers that connect to the interdigitated electrodes. The pitch between the metal fingers is 920 um and repeats over the entire back surface of the panel.

All three manufacturers employ some sort of surface texturing along with anti-reflective coatings to reduce reflection but SunPower uses the most advanced technology for surface texturing. FIGURE 7 illustrates a SEM topographical image of the front surface texture of the monocrystalline substrate having pyramids, which are etched into the silicon surface. These faceted surfaces increase the probability of reflected light entering back to the surface of the substrate. A similar concept is also applied to the back surface.

The future is sunny and bright

Of the three panels we analyzed, SunPower solar panels employ the most advanced technologies and they illustrate how the solar cell has evolved over the ages. It started from a simple PN junction, then passivated emitters were intro- duced along with local back-surface-field (BSF) technology, which came to be known as Passivated-Emitter with Rear Locally (PERL) diffused technology. In contrast, today the most advanced technology is interdigitated back contacts along with passivated contacts.

In addition to these advances, there is great progress in tandem cells and multi-junctions to capture the different wavelength regions of the sun’s rays. A recent article in IEEE spectrum magazine presented the state of art of record-breaking PV cells made with different techniques such as thin film, crystalline Si, single junction, multi-junction cells. PV cells especially the multi-junction cells, have now crossed the 50% efficiency barrier [12]. Similarly, a publication from the alterenergy.org has collected all the major advances made in PV technology and discusses concepts like colloidal quantum dots and GaAs for cell technology, along with new applications [13]. Today, we regularly read about new materials (like perovskites) and come across new techniques that improve solar panel efficiencies, including new manufacturing methods to reduce the overall cost of fabrication. Moreover, PV cells are used in an innovative manner. The installation of PV panels is no more restricted to isolated rooftops or solar farm. An article in the Guardian made a reference to a solar panel road in Normandy, France [14]. At TechInsights, we will continue to keep an eye on emerging solar cell technologies.

The efforts emerging from various organizations all over the world are very encouraging. There are indeed many challenges for renewable energy to overcome before fiscal parity with fossil fuels is achieved; particularly for PV energy. Nevertheless, there is an increased focus on climate change issues. This has resulted in a significant amount of resources being allotted to PV technology in many countries, especially in developing countries such as China, India, and Brazil [1, 2]. This optimistic scenario reminds us of the song “I Can See Clearly Now” by the 1970s American singer Johnny Nash, where the refrain runs optimistically, “It’s gonna be a bright, bright sun-shiny day.”

References

1. http://www.renewableenergyworld.com/articles/2017/01/21-mw- of-solar-pv-for-emerging-market-community-mini-grids-announced- since-april.html;
2. http://www.pv-magazine.com/news/details/beitrag/iea-pvps— installed-pv-capacity-at-227-gw-worldwide_100024068/#ixzz4MB1 a44hq
3. The history of solar: https://www1.eere.energy.gov/solar/pdfs/solar_ timeline.pdf
4. http://news.ihsmarkit.com/press-release/technology/ihs-markit- names-trina-solar-sunpower-first-solar-hanwha-q-cells-and-jinko-
5. www.pv-tech.org/guest…/n_type_silicon_solar_cell_technology_ ready_for_take_off
6. http://www.itrpv.net/; http://www.itrpv.net/Reports/Downloads/2016/ 7. http://www.solar-facts-and-advice.com/amorphous-silicon.html
8. http://energyinformative.org/solar-cell-comparison-chart-mono-
polycrystalline-thin-film/
9. RP_0706-14839-O-4CS-11Kaneka
10. RP_0616-41931-O-5SA-100_Trina
11. RP_0716-42662-O-5SA-100_SunPower
12. http://spectrum.ieee.org/green-tech/solar/what-makes-a-good-pv-
technology
13. http://www.altenergy.org/renewables/solar/latest-solar-technology.
html
14. https://www.theguardian.com/environment/2016/dec/22/solar-panel-
road-tourouvre-au-perche-normandy

Advancements in spintronics

September 25, 2017

BY HIDEO OHNO, MARK STILES, and BERNARD DIENY, IEEE

Spintronics is the concept of using the spin degree of freedom to control electrical current to expand the capabilities of electronic devices. Over the last 10 years’ considerable progress has been made. This progress has led to technologies ranging from some that are already commercially valuable, through promising ones currently in development, to very speculative possibilities.

Today, the most commercially important class of devices consists of magnetic sensors, which play a major role in a wide variety of applications, a particularly prominent example of which is magnetic recording. Nonvolatile memories called magnetic random access memories (MRAMs) based on magnetic tunnel junctions (MTJs), are commercial products and may develop into additional high impact applications either as standalone memories to replace other random access memories or embedded in complementary metal–oxide–semiconductor (CMOS) logic.

Some technologies have appealing capabilities that may improve sensors and magnetic memories or develop into other devices. These technologies include three- terminal devices based on different aspects of spin-transfer torques, spin-torque nano-oscillators, devices controlled by electric fields rather than currents, and devices based on magnetic skyrmions. Even further in the future are Spintronics-based applications in energy harvesting, bioinspired computing, and quantum technologies.

But before we get into detail about where Spintronics is today, we need to cover the history of Spintronics.

The history of spintronics

Spintronics dates to the 1960s and was discovered by a group at IBM headed by Leo Esaki, a Japanese physicist who would later go on to win a share of the Nobel Prize I 1973 for discovering the phenomenon of electronic tunneling. Esaki and his team conducted a study which showed an antiferromagnetic barrier of EuSe sandwiched between metal electrodes exhibits a large magnetoresistance.

Subsequent advances of semiconductor thin film deposition techniques such as molecular beam epitaxy led to the development of semiconductor quantum structures, which prompted studies of magnetic multilayers. Ensuing studies of magnetic multilayers resulted in the discovery of giant magne- toresistance (GMR) in 1988. This effect was used to make magnetic sensors, which boosted the areal density of information stored on hard disk drives and led to the 2007 Nobel Prize in Physics awarded to Albert Fert and Peter Grunberg.

Since then rapid progress has continued to enhance both the role and the potential of Spintronics. So, let’s take a look at where we are now.

Where we are now

Applications now include nanoscale Spintronics sensors that further enhance the areal density of hard disk drives, through MRAMs that are seriously being considered to replace embedded flash, static random access memories (SRAM) and at a later stage dynamic random access memories (DRAM). Applica- tions also include devices that utilize spin current and the resulting torque to make oscillators and to transmit information without current.

Now let’s look at those applications and more in-depth.

Modern Hard Disk Drives: Two breeds of Spintronics sensors have replaced traditional anisotropic magnetoresistance (AMR) sensors. Those sensors include giant magnetoresistance (GMR) sensors (used in hard disk drives between 1998 and 2004) and tunnel magnetoresistance (TMR) sensors (used since 2004).

Those sensors are part of the technology development that enabled the increase of storage density of hard disk drives by several orders of magnitude, laying the foundation of today’s information age in the form of data centers installed by the cloud computing industry.

Magnetoresistive Random Access Memory (MRAM): MRAM and particularly spin-transfer- torque MRAM (STT-MRAM) is a nonvolatile memory with very high endurance and scalability. The current STT-MRAM technology uses an array of MTJs with an easy axis of magnetization oriented out of the plane of the layers. These MTJs utilize interface perpendicular anisotropy at the CoFeB–MgO interface, along with the large TMR of the system, for reading the state of magnetization. The spin-transfer torque exerted by a spin polarized current is used to change the magneti- zation direction, offering an efficient way of rewriting the memory. FIGURE 1 show the main families of MRAM that have evolved since 1995.

Three Terminal Magnetic Memory Devices: Recent physics developments raise the prospect of three- terminal spintronic memory devices. These devices have an advantage over the standard two-terminal devices used in memory applications such as MRAM in that separating the read and write functions poten- tially overcomes several future roadblocks in the devel- opment of MRAM. There are two writing schemes: one is based on spin currents generated by an electrical current running through a heavy metal adjacent to the free layer of the MTJ. The current causes a spin current both in the bulk of the heavy metal and at the interface; this spin current then exerts a torque, called the spin-orbit torque, on the magnetization. In this scheme, the write current does not pass through the MTJ, separating the write and read functions. The other scheme uses current-induced domain wall motion to move a domain wall in the free layer of the MTJ from one side of the fixed layer to the other. In this scheme, the current passes through the free layer, but not the tunnel barrier, again separating the read and write functions.

Standby-Power-Free Integrated Circuits Using MTJ-Based VLSI Computing: Spintronic-based nonvolatile embedded working memory used in conjunction with CMOS-based logic applications is a crucial first step toward standby-power-free logic circuits that are much needed for Internet of Things (IoT) applications. MRAM based logic-in-memory reduces the overhead of having memory and logic apart and gives both minimized interconnection delay and nonvolatility.

Security: These devices have shown great promise for logic and memory applications due to their energy efficiency, very high write endurance, and nonvolatility. Besides, these systems gather
many entropy sources which can be advantageously used for hardware security. The spatial and temporal randomness in the magnetic system associated with complex micromagnetic configurations, the nonlinearity of magnetization dynamics, cell-to-cell process variations, or thermally induced fluctuations of magnetization can be employed to realize novel hardware security primitives such as physical unclonable functions, encryption engines, and true random number generators.

Spin-Torque and Spin-Hall Nano-Oscillators: Spin-torque nano-oscillators (STNO) and spin-Hall effect nano-oscillators (SHNO) are in a class of miniaturized and ultra-broadband microwave signal generators that are based on magnetic resonances in single or coupled magnetic thin films. These oscil- lators are based on magnetic resonances in single or combined magnetic thin films where magnetic torques are used to both excite the resonances and subsequently tune them. The torques can be either spin-transfer torques due to spin-polarized currents (STNOs) or spin Hall torques due to pure spin currents (SHNOs). These devices are auto-oscillators and so do not require any active feedback circuitry with a positive gain for their operation. The auto-oscillatory state is strongly nonlinear, causing phase– amplitude coupling, which governs a wide range of properties, including frequency tunability, modulation, injection locking, mutual synchronization, but also causes significant phase noise. STNOs and SHNOs can, in principle, operate at any frequency supported by a magnetic mode, resulting in a potential frequency range of over six orders of magnitude, from below 100 MHz for magnetic vortex gyration modes to beyond 1 THz for exchange dominated modes. Since STNOs and SHNOs can also act as tunable detectors over this frequency range, there is significant potential for novel devices and applications.

Beyond the applications listed, the spin degree of freedom is also being used to convert heat to energy through the spin Seebeck effect, to manipulate quantum states in solids for information processing and communication, and to realize biologically inspired computing. These may lead to new develop- ments in information storage, computing, communication, energy harvesting, and highly sensitive sensors. Let’s take a look at these new developments.

Thermoelectric Generation Based on Spin Seebeck Effects: The study of combined heat and spin flow, called spin caloritronics, may be used to develop more efficient thermoelectric conversion. Much of the focus of research in spin caloritronics has been the longitudinal spin Seebeck effect, which refers to spin-current generation by temperature gradients across junctions between metallic layers and magnetic layers. The generated spin current in the metallic layer gets converted into a charge current by the inverse spin Hall effect, making a two-step conversion process from a thermal gradient perpen- dicular to the interface into a charge current in the plane of the interface. This process can be used for thermoelectric conversion. Device structures using the spin Seebeck effect differ significantly from those using conventional Seebeck effects due to the orthog- onality of the thermal gradient and resulting charge current, giving different strategies for applications of the two effects.

Electric-Field Control of Spin-Orbit Interaction for Low-Power Spintronics: Control of magnetic properties through electric fields rather than currents raises the possibility of low energy magnetization reversal, which is needed for low-power electronics and Spintronics. One specific way to accomplish this low energy switching is through electric-field control of electronic states leading to modification of the magnetic anisotropy. By applying a voltage to a device, it is possible to change the anisotropy such that the magnetization rotates into a new direction. While such demonstrations of switching alone are not sufficient to make a viable device, voltage controlled reversal is a promising pathway toward low-energy nonvolatile memory devices.

Control of Spin Defects in Wide-Bandgap Semiconductors for Quantum Technologies: The spins in deep level defects found in diamond (nitrogen- vacancy center) and in silicon carbide (divacancy) have a quantum nature that manifests itself even at room temperature. These can be used as extremely sensitive nanoscale temperature, magnetic-field, and electric-field sensors. In the future, microwave, photonic, electrical, and mechanical control of these spins may lead to quantum networks and quantum transducers.

Spintronic Nanodevices for Bioinspired Computing: Bioinspired computing devices promises low-power, high-performance computing but will likely depend on devices beyond CMOS. Low-power, high performance bioinspired hardware relies on ultrahigh- density networks built out of complex processing units interlinked by tunable connections (synapses). There are several ways in which spin-torque-driven MTJs, with their multiple, tunable functionalities and CMOS compatibility, are very well adapted for this purpose. Some groups have recently proposed a variety of bioin- spired architectures that include one or several types of spin-torque nanodevices.

Skyrmion-Electronics: An Overview and Outlook: The concept of skyrmions derives from high energy physics. In magnetic systems, skyrmions are magnetic textures that can be viewed as topological objects. Theory suggests that they have properties that might make them useful objects in which to store and manip- ulate information. Many of the ideas are similar to ideas that were developed decades ago for bubble memory or, more recently, racetrack memory. There are several possible advantages for skyrmion devices as compared to other related devices. They are potentially higher density and lower energy, although the arguments for these remain to be experimentally verified.

So, what does the future of spintronics have in store?

The future

Spintronics will continue to have increasing impact, but the future is somewhat uncertain. The importance of magnetic sensors is likely to remain important while the importance of the magnetic sensors in hard disk drives appears to depend on the economics of mass storage in the cloud.

MRAM seems likely to play an increasing role both as standalone memory and embedded in CMOS. The degree of adoption still depends on a few technical and many economic considerations. The acceleration, over the past few months, of announcements and demonstrations related to STT-MRAM produced by major microelectronics companies, seems to indicate that large volume production of STT-MRAM is getting quite close. If the adoption of this technology by microelectronics industry becomes a reality, the whole field will be strongly boosted.

In the future, Spintronics can play a critical role in areas such as IoT, ultralow-power electronics, high-performance computing (HPC). Besides, in the next 10 to 15 years, we are likely to see a much greater role played by alternative forms of computing. The role that Spintronics plays in those technologies is likely to be strongly influenced by the success of MRAM. If MRAM is successful, we will have developed the ability to manufacture it making it easier to import into other technologies.

Some of the recent technical developments that have significant virtues for applications will likely play a role in technology 10 to 15 years from now but many will not. Research on many of these ideas will continue and will spawn related areas. Material research is key along this road.

Innovative materials allowing efficient charge to spin and spin to charge current conversion, or good control of magnetic properties by voltage, or efficient injection/manipulation/detection of spins in semicon- ductors can play major roles. Along with this idea, the use of oxide materials in spintronic devices can become quite important. Oxides share crystal- linity with semiconductors in distinction to metallic magnetic devices. Will the greater control that comes with crystallinity give advantages to oxides in future devices? These are some of the many topics that are likely to be addressed in the coming years.

Laser marking meets diverse challenges in fab and packaging

September 22, 2017

The basics of laser marking are reviewed, as well as current and emerging laser technologies.

BY DIETRICH TÖNNIES, Ph.D. and DIRK MÜLLER, Ph.D., Coherent Inc., Santa Clara, CA

Laser marking is established at multiple points in semiconductor production and applications continue to diversify. There are several laser technologies servicing the application space. This article reviews the basics of laser marking and the current and emerging laser technologies they utilize. It is intended to give a clear sense of what applications parameters drive the choice of laser (speed, cost, resolution, etc.), and provide those developing a new application some guidance on how to select the optimum technology.

Laser marking basics

Laser marking usually entails inducing a visible color or texture change on a surface. Alternatively, although less commonly, marking sometimes involves producing a macroscopic change in surface relief (e.g.engraving). To understand what laser type is best for a specific marking application, it is useful to examine the different laser/ material interactions that are generated by commonly used laser types.

Most frequently, lasers produce high contrast marks through a thermal interaction with the work piece. That is, material is heated until it undergoes a chemical reaction (e.g. oxidation) or change of crystalline structure that produces the desired color or texture change. However, the particulars of this process vary significantly between different materials and laser types.

CO2 lasers have been employed extensively for PCB marking because they provide a fast method of producing high contrast features. However, they are rarely selected when marking at the die or package level. This is because the focused spot size scales with wavelength due to diffraction. CO2 lasers emit the longest infrared (IR) output of any marking laser. Additionally, IR penetrates far into many materials, which can cause a substantial thermal impact on surrounding structures. Consequently, CO2 laser marking is limited to producing relatively large features where a significant heat affected zone (HAZ) can be tolerated.

Fiber lasers, which offer high power output in the near IR, have emerged over the past few years as one of the most cost effective tools for high-speed marking. Furthermore, the internal construction of fiber lasers renders a compact footprint, facilitating their integration into marking and test handlers. Cost and space savings are further enhanced when the output of a single, high power fiber laser is split, feeding two scanner systems.

But fiber lasers have disadvantages, too. One reason for the low cost of many fiber lasers is that they are produced in high volumes with designs meant for general-purpose applications. For example, they usually produce a high quality beam with a Gaussian intensity profile. This is advantageous for many material processing applications, but not always for laser marking. In fact, a more uniform beam intensity distribution, called a flat-top profile, is sometimes more useful since it produces marks with a sharper, more abrupt edge (rather than a smooth transition from the marked to the unmarked region). Coherent recently introduced a new type of fiber (NuBEAM Flat-Top fiber technology) which enables efficient conversion of single-mode laser beams into flat-top beam profiles, specifically to address this issue.

Other quality criteria, such as high-purity linear polarization, and stability of pulse energy and pulse width, are difficult to achieve with low-cost fiber lasers. This limits their use in more stringent or sensitive marking applications. From a practical standpoint, most fiber lasers cannot be repaired in the field, but are replaced as a whole. This leads to longer equipment downtime and increased maintenance efforts as compared to traditional marking lasers based on diode-pumped, solid-state (DPSS) technology (specifically, DPSS is used here to refer to lasers with crystal resonators).

DPSS lasers also emit in the near infrared. Generally, these lasers are more expensive than a fiber laser of the same output power level. So, infrared DPSS lasers are most commonly used in applications having technical requirements that cannot be met by fiber lasers,such as high volume production of more advanced and expensive semiconductor devices.

One advantage of DPSS laser technology is that it can be configured to directly produce a multi-mode beam profile which is essentially flat-top. The Coherent ❘ Rofin PowerLine E Air 30-1064 IC is an example which has found extensive use in semiconductor marking, since it provides an efficient way to rapidly produce very high contrast marks.

Another useful feature of DPSS lasers, which produce pulsewidths in the nanosecond regime, is that their output is much more stable than that of fiber lasers. This makes it much easier to reliably frequency double or triple their infrared light within the laser head, giving a choice of output in the green or ultraviolet (UV). Output at these wavelengths provides two significant benefits. First, they offer additional options in matching the absorption of the material to the laser wavelength. Stronger absorption generally yields higher marking efficiency and reduced HAZ, since the laser light doesn’t penetrate as far into the material. The second benefit of shorter wavelengths is the ability to focus to smaller spot sizes (because of their lower diffraction) and produce smaller, finer marks.

However, frequency multiplied DPSS lasers are generally more costly and voluminous than either fiber lasers or infrared DPSS lasers with comparable output power. Lower power translates into reduced marking speed.

Therefore, green and UV DPSS lasers are typically employed when they offer a significant advantage due to the particular absorption characteristics of the material(s) being marked.

Another emerging and important class of marking lasers has pulsewidths in the sub-nanosecond range. Due to the nature of the laser/material interaction at short pulsewidths, these lasers tend to produce the smallest possible HAZ with excellent depth control.

There are just a few products currently on the market that exploit this property. One example is the PowerLine Pico 10 from Coherent ❘ Rofin which generates 0.5 ns laser pulses in either the near IR (8 W total power) or green (3 W total power), at pulse repetition rates between 300 kHz and 800 kHz. This combination of output characteristics makes it capable of high speed marking of a wide range of materials where mark penetration depth must neces- sarily be shallow because of low material thickness, or to minimize HAZ.

Laser marking today

Typically, the first consideration in choosing a laser for a specific application is matching the absorption characteristics of the material with the laser wavelength. Similarly, desired feature size is also driven by laser wavelength, as well as by the precision of the beam scanning system. Next, HAZ constraints usually determine the maximum pulsewidth which can be used (although this choice is again highly material dependent). To see how these parameters interact in practice, it’s useful to review some real world applications.

Epoxy-based molding compounds

The most commonly used molding compounds absorb very well in the near IR. Specifically, the near IR laser transforms the usually black molding compound into a gray/white powder, yielding high contrast marks. Plus, many IC packages have mold compound caps thick enough to easily tolerate a marking depth of 30 μm to 50 μm. As a result, many marking systems based on near IR lasers, both fiber and DPSS, are currently in use.

However, some semiconductor devices with small form factor have only thin mold compound caps to protect wire bonded silicon dies, and a marking depth of only 10 μm or less is required. Increasingly, green lasers are used for this type of shallow marking because of a stronger absorption at this wavelength by the epoxy matrix.

Ceramics

The process window when marking ceramics, such as used in packaging power semiconductors, high-brightness LEDs, RF devices, saw filters or MEMS sensors, is relatively narrow. Accurate focus and high pulse energy are critical to ensure reliable marking results, and ideally, the laser marker should have the capability to adjust the focus of the laser beam onto the ceramic surface in real time, in order to compensate for package height variations. Because of their more reliable interaction with ceramic materials, DPSS lasers based on Nd:YAG, which offer high pulse energies and relatively long pulses, are often still used for marking ceramic lids and substrates. Coherent ❘ Rofin has also developed a special fiber laser (the PowerLine F 20 Varia IC), which offers adjustable pulse widths up to 200 ns, specifically to improve process windows for marking applications of this type.

The ceramic substrates used with high-power LEDs often require tiny marks to identify individual devices. IR lasers are the preferred lasers for marking these ceramic substrates, providing their spot size is not too big for the layout to be marked. For very small marking features a green laser or UV laser is often required.

Organic substrates

IC substrates or interposers are marked during production with traceable data matrix codes. The thin green solder resist layer on top of the substrate has to carry the mark, and care has to be taken that the copper underneath the solder resist is not exposed. Moreover, data matrix codes can be quite small, with cell sizes of only 125 μm or even less. Since the spot size of the focused laser beam must thus be much smaller than the cell size, the final spot diameter must be significantly less than 100 μm.

Defective IC substrates often are identified by marking large features (e.g., a cross) into the solder resist layer. Although the part is defective, the properties of the mark are still important. This is because it has to be reliably recognized by subsequent processing tools, and also, because any delamination of the solder resist layer might cause problems during succeeding processes.

IC strips have gold pads along their periphery which are used to identify parts found to be defective after die attach and wire bonding. For defective parts, the gold pad is marked by converting its color from gold to black or to dark grey.

Ideally, it is desirable to have one laser marker that can accomplish all three of these marking applications tasks. The green DPSS laser has become the standard laser marker for these applications, with UV lasers occasionally employed for high-end substrates.

Semiconductors

The growing demand for flip-chip devices, wafer-level packaging and defective die identification drives the need for direct marking of silicon, GaAs, GaN/sapphire or other semiconductors. Silicon is partially trans- parent in the near IR, and lasers at this wavelength are used whenever deep marks into silicon are required, such as placing wafer IDs near the wafer edge. Near IR laser markers are also selected for marking molded fan-out wafer level packaging wafers.

However, for marking either flip-chips or the backside of wafers, green lasers are preferred because of the strong absorption of this wavelength in silicon. Wafer backside marking requires only very shallow marks and the shallow laser penetration avoids potential damage to the circuitry on the reverse side of the flip-chip or wafer. The need for shallow marking also minimizes the laser power requirement. For example, Coherent ❘ Rofin provides a 6 W green laser (the PowerLine E 12 SHG IC) that is well suited for wafer backside marking, and can also mark the wafer through the tape whenever the wafer is mounted on a film frame.

Metals

Near IR lasers are widely used for marking the metal lids used with microprocessors and other high power consumption ICs.

Leadframes, which are plated with tin, silver or gold, are marked either before or after plating. Since leadframes are used for cost sensitive devices, capital investment is critical, and economical fiber lasers are often chosen for this reason.

Laser marking tomorrow

As packages get thinner and smaller, they will require shallower, higher resolution marks. Sub-nanosecond lasers are the most promising method for producing these types of marks, and are compatible with a wide range of materials. The diverse capabilities of this technology are shown in Figure 5, which depicts marking results on four different materials using a sub-nanosecond laser (Coherent ❘ Rofin PowerLine Pico 10-532 IC).

The first image is a flexible IC substrate; very thin solder resist layers and metal coatings make it important that the laser does not cause delamination. Here, the circular gold pad has been converted to black without delamination. In the next image, an IC substrate has been given a white mark, again without delaminating the solder resist.

The third image shows very small characters (< 150 μm) marked on the backside of a silicon wafer containing hundred thousands of tiny discrete semiconductor devices. Producing marks of this resolution through the film would be difficult to accomplish with a nanosecond pulsewidth laser.

The final image is a copper leadframe coated with thin silver film. Here, the goal is to produce a shallow mark with high contrast without engraving the under- lying material, which has been accomplished with the sub-nanosecond laser.

Conclusion

Semiconductor fabrication and packaging represent challenging marking applications, often requiring small, fine marks produced without a significant effect on surrounding material. An overall trend towards smaller and thinner device geometries will drive increased use of higher precision laser tools, such as those utilizing green and UV nanosecond lasers, and even sub-nanosecond lasers, while cost-sensitive applications will continue to utilize inexpensive fiber lasers.

Leading-edge paves the way for pure-play foundry growth

September 20, 2017

IC Insights has just released its September Update to The McClean Report. This 32-page Update includes a detailed look at the pure-play foundry market and an analysis of the historical DRAM price-per-bit trends. Shown below is an excerpt from the Update that examines the IC technology trends in the pure-play foundry market.

In 2017, the 7% increase in the total pure-play foundry market is forecast to be almost entirely due to an 18% jump in <40nm feature size device sales (Figure 1).

Figure 1

Although expected to represent 60% of total pure-play foundry sales in 2017, the ≥40nm pure-play IC foundry market is forecast to be up only $0.2 billion this year. In contrast, the 2017 leading-edge <40nm pure-play foundry market is expected to surge by a hefty $3.3 billion. Moreover, not only is almost all of the pure-play foundry growth forecast to come from leading-edge production in 2017, most of the profits that are expected to be realized in the foundry market also forecast to come from the finer feature sizes as well.

TSMC is by far the technology leader among the major pure-play foundries. In 2017, 58% of TSMC’s revenue is expected to come from <40nm processing, more than double percentage at GlobalFoundries and more than triple the share at UMC. In total, TSMC is forecast to hold an 86% share of the total <40nm pure-play foundry market this year.

Illustrating how dominant TSMC is in the leading-edge pure-play foundry market, the company is expected to have almost 7x the dollar volume sales at <40nm as compared to GlobalFoundries, UMC, and SMIC combined this year ($18.5 billion for TSMC and $2.7 billion for combined total of GlobalFoundries, UMC, and SMIC). In fact, 10% of TSMC’s total sales this year are forecast to be for its 10nm process technology.

In contrast to TSMC, SMIC only entered initial production of its 28nm technology in 4Q15, more than three years after TSMC first put its 28nm process into production. In fact, only 7% of SMIC’s 2017 sales are expected to be from devices having 28nm feature sizes (the company does not offer a finer feature size at this time), which is the primary reason its revenue per wafer is so much less compared to TSMC.

DARPA calls for Monolithic 3D â 3DSoC

September 19, 2017

By Zvi Or-Bach, President and CEO of MonolithIC 3D Inc.

On Sept 13, DARPA come out with Electronic Resurgence Initiative (ERI) programs. Quoting: “with an eye toward the times we now live in, [Gordon Moore] laid out the technical directions to explore when the conditions under which scaling will be the primary means for advancement are no longer met. A trio of simultaneously-released ERI BAAs—this one among them—parallel the research areas detailed on page three of Moore’s paper: materials and integration, architecture, and design. These new page-three-inspired investments, along with a series of related investments from the past year, comprise the overall Electronics Resurgence Initiative.”

Among these programs is the “Three Dimensional Monolithic System-on-a-Chip (3DSoC): Develop 3D monolithic technology that will enable > 50X improvement in SoC digital performance at power.”

In perfect timing, this year’s IEEE S3S 2017 at the Hyatt Regency at the San Francisco Airport will feature a comprehensive show case for monolithic 3D IC technologies.

At the start Al Fazio, Intel Senior Fellow, will give a plenary talk on how 3D NAND and 3D XPoint™ happened to be the trailblazing monolithic 3D IC technologies that have matured to volume production, taking over the fast growing memory market. The first day will end with two 3D IC focus sessions comprised of a mix of invited and submitted papers covering exotic technologies and the use of the emerging nano-wire transistor for 3D scaling.

The first half of the second day includes a collaborative event organized by Qualcomm and CEA Leti – the COOLCUBE/3DVLSI Open Workshop. The second half will include an open 3D tutorial providing full coverage of the various 3D integration technologies from TSV to Sequential Integrations.

The third day of the conference will include a full day with four sessions of invited and submitted talks on monolithic and other forms of 3D integration. These sessions will include a talk by us, MonolithIC 3D Inc., in which we will present a monolithic 3D technology that is ready to be rapidly deployed using the current transistor process. In that talk we will also describe how such an integration technology could be used to improve performance, reduce power and cost of most computer systems, suggestive of a 1,000x total system benefit.

In addition, the IEEE S3S conference will have full coverage of SOI and low power technologies, making it the place to be and to learn about alternative technologies to dimensional scaling. I am looking forward to seeing you at the S3S from October 16th thru 19th, 2017.

Soitec launches FD-SOI pilot line in Singapore

September 13, 2017

Soitec, a designer and manufacturer of semiconductor materials for the electronics industry, is launching a pilot line to produce fully depleted silicon-on-insulator (FD-SOI) wafers in its Singapore wafer fab. This is the first stage in beginning FD-SOI production in Singapore and providing multi-site FD-SOI substrate sourcing to the global semiconductor market.

“Our decision to launch this FD-SOI line in Singapore as well as the decision we already made to ramp up our FD-SOI production in France are based on direct customer demand,” said Paul Boudre, CEO of Soitec. “These are very important milestones for Soitec and the expanding FD-SOI ecosystem. In Singapore, we plan to get full qualification at the customer level in the first half of 2019 and then increase capacity in line with market commitment.”

The FD-SOI ecosystem continues to strengthen and the use of FD-SOI technology is progressing. Multiple foundries, IDMs and fabless customers are engaged with a growing number of FD-SOI tape-outs and wafer starts. FD-SOI offers a unique value proposition for low-power applications, which makes it well suited for rapidly growing electronic market segments such as mobile processing, IoT, automotive and industrial.

Soitec reports that its investment in Singapore to launch its FD-SOI pilot line is approximately US$40 million, to be spent over a 24-month period.